diff --git a/src/crop/almass.jl b/src/crop/almass.jl
index 39a9f83f04dccde3b1a1cb1a5f1e43d3fc44091d..90e2c582fad59dc9fed7d56b234223dad7b21788 100644
--- a/src/crop/almass.jl
+++ b/src/crop/almass.jl
@@ -3,12 +3,6 @@
 ### This file is responsible for managing the crop growth modules.
 ###
 
-#FIXME Looking at fields.pdf in the Persefone output, crop maturity is not recognised
-# properly, so most crops (except maize) are never planted. At the same time, maize never
-# seems to start growing.
-
-#TODO write tests to compare our output to the output of the original ALMaSS algorithm
-
 # Some functions translated from ALMaSS for use in Persefone.jl
 #
 # ALMaSS is licensed as follows:
@@ -33,6 +27,13 @@
 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+
+#FIXME Looking at fields.pdf in the Persefone output, crop maturity is not recognised
+# properly, so most crops (except maize) are never planted. At the same time, maize never
+# seems to start growing.
+
+#TODO write tests to compare our output to the output of the original ALMaSS algorithm
+
 module ALMaSS
 
 ## The two input files required by ALMaSS. Must be present in the crop directory.
@@ -557,41 +558,15 @@ function find_diff(dds::Vector{Float64}, slopes::Vector{T}, ddegs::Float64, ydde
     # more than a single inflection point in the growth curve in a
     # single day...
 
-    # n = length(dds)
-    # oldindex = 1
-    # newindex = 1
+    # Note: the code is slightly different to the original ALMaSS
+    # code, which I think is caused by ALMaSS not storing the -1 entry
+    # in the dds array.
 
     if first(dds) == 99999.0
         return 0.0 * oneunit(T)  # zero(T) does not work when slopes has units
     end
 
-    # for i = 1:n-1
-    #     if dds[i + 1] > ddegs
-    #         newindex = i
-    #         break
-    #     end
-    # end
-    # for i = 1:n-1
-    #     if dds[i + 1] > yddegs
-    #         oldindex = i
-    #         break
-    #     end
-    # end
-
-    # # Note/TODO: we skip over the first datapoint if dds[1] == -1
-    # # (which means that this is not a slop but should set the
-    # # height/LAgreen/LAtotal).  Presumably the original ALMaSS code
-    # # does not include these points with the slopes.
-    # if dds[1] == -1
-    #     if oldindex == 1
-    #         oldindex = 2
-    #     end
-    #     if newindex == 1
-    #         newindex = 2
-    #     end
-    # end
-
-    function get_index(array::T, threshold::eltype(T)) where {T <: DenseArray}
+    function get_index(array::Tarr, threshold::eltype(Tarr)) where {Tarr <: DenseArray}
         idx = findfirst(x -> x > threshold, array)
         if isnothing(idx)
             idx = lastindex(array) + 1
@@ -614,19 +589,14 @@ function find_diff(dds::Vector{Float64}, slopes::Vector{T}, ddegs::Float64, ydde
         # We have passed an inflection point between today and yesterday.
         # First add the increment from yesterdays day degree sum up to
         # the inflection point.
-        # dddif = dds[newindex] - yddegs
-        # diff = slopes[oldindex] * dddif
         dddif = dds_newindex - yddegs
         diff = slopes_oldindex * dddif
 
         # Then from the inflection point up to today.
-        # dddif = ddegs - dds[newindex]
-        # diff += slopes[newindex] * dddif
         dddif = ddegs - dds_newindex
         diff += slopes_newindex * dddif
     else
         # No inflection point passed
-        # diff = slopes[newindex] * (ddegs - yddegs)
         diff = slopes_newindex * (ddegs - yddegs)
     end
     return diff